commit 4be735225f7cd040ca81c18740e7b672021bafeb
author Eric Dumazet <edumazet@google.com> Mon Apr 25 10:39:34 2016 -0700
committer David S. Miller <davem@davemloft.net> Wed Apr 27 23:08:40 2016 -0400
tree 36276766d7de862ca9ade5b3d32303439c1d18ad
parent 9317bb69824ec8d078b0b786b6971aedb0af3d4f

net: SOCKWQ_ASYNC_WAITDATA optimizations

SOCKWQ_ASYNC_WAITDATA is set/cleared in sk_wait_data()
and equivalent functions, so that sock_wake_async() can send
a SIGIO only when necessary.

Since these atomic operations are really not needed unless
socket expressed interest in FASYNC, we can omit them in most
cases.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sock.h

diff --git a/include/net/sock.h b/include/net/sock.h
index 0f48aad..3df778c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1940,7 +1940,8 @@
  */
 static inline void sk_set_bit(int nr, struct sock *sk)
 {
-	if (nr == SOCKWQ_ASYNC_NOSPACE && !sock_flag(sk, SOCK_FASYNC))
+	if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
+	    !sock_flag(sk, SOCK_FASYNC))
 		return;
 
 	set_bit(nr, &sk->sk_wq_raw->flags);
@@ -1948,7 +1949,8 @@
 
 static inline void sk_clear_bit(int nr, struct sock *sk)
 {
-	if (nr == SOCKWQ_ASYNC_NOSPACE && !sock_flag(sk, SOCK_FASYNC))
+	if ((nr == SOCKWQ_ASYNC_NOSPACE || nr == SOCKWQ_ASYNC_WAITDATA) &&
+	    !sock_flag(sk, SOCK_FASYNC))
 		return;
 
 	clear_bit(nr, &sk->sk_wq_raw->flags);